The Spiegel reported Saturday that Siemens is pressuring Russian atomic energy agency Rosatom over its involvement in building Iran's first power plant in the southern port of Bushehr. The Munich-based Siemens launched a joint venture Rosatom on Tuesday, forecasting the construction of some 400 new nuclear power plants worldwide by 2030. Siemens CEO Peter Loescher initially hailed the joint venture as a great opportunity "to enlarge our footprint in nuclear business with a very strong and experienced partner." He later became critical of Russia's political and financial contributions to the Bushehr reactor and demanded that the Kremlin address international concerns over Tehran's uranium enrichment activities. The ongoing Russian cooperation with Iran has prompted Siemens -- widely believed to be the largest engineering firm in Europe -- to reduce business with Russia only a week after its deal was sealed, Spiegel revealed. Washington, Tel Aviv and their European allies accuse Tehran of inching toward nuclear weapons development. Iran, however, dismisses the allegation, saying its uranium enrichment is aimed at peaceful energy production. Moscow has supplied nuclear fuel for the Bushehr power plant since 2007 under arrangements with the International Atomic Energy Agency. Western countries have criticized Moscow's involvement in building the Bushehr plant. Russia, however, insists that the Bushehr plant -- which was completed under a USD 1 billion contract -- is purely civilian and cannot be used for weapons production. The 1000-megawatt reactor is expected to become operational later this year.